Improvement in bolt-blanks



UNITED STATEs PATENT OEEIeE.l d/

JAMES B. CLARK, OF PLANTSVILLE, CONNECTICUT.

IMPROVEMENT IN '.BOLT-BLANKS.

Spect'jication ffwming part of Letters Patent No. 96,308, dated November2, 1869.

To all whom it may concern:

Be it known that I, JAMES B. CLARK, of Plantsville, in the county ot'Hartford, State of Connecticut, have invented a new and Improved Blankfor Carriage-Bolts; and I do hereby declare that the following is afull,

l a blank from which a bolt is to be forged, with both of its endsround, while the portion designed to be squared is formed into the shapeot' the frustum ot' a cone, with the base thereof larger than thediameter ot1 the aforesaid ends, and adjoining the end of the blankwhich is to remain round.

In Fig. 1, A designates the round end of the blank, from which the headis to be formed. B designates the conical or tapering portion whichis tobe squared in heading, while C designates the end that will remain roundand unchanged in forging the bolt.

The blanks are made of round iron of the proper size to form the screwpart of the bolt, and may be upset so as to form the taper B in ally'pI'Opel' lll'rtflllef.`

.I upset the same by first heating the lower portion ot' the part to besquared, and then clamp the round end C in a proper clamp. Blowsorpressure are then brought to bear on the end A, which will upset theblank, as shown at B, Fig. 1.

1f desired, the blank could'be formed of iron a little larger thandesigned to leave the round end C by forging the blanks in suitable diesunder a power-hammer or a similar machine. The base of the taper Bshould be of such size that it can be squared into a square the sides ofwhich are equal to the diameter of the end C, while the top of the taperB should be -of the same diameter as the lends'A and C. The blanks whenthus constructed are again placed in a proper furnace, so as to heat theend A and taper B, and then inclosed in an ordinary heading-die with theend C downward, and the die is then closed, which will square the baseof the taper B.

As only a small portion of the taper is of the proper size to make asquare of the desired size, it will readily be perceived that only asmall amount of pressure will be necessary to close the dies.` When thedies are so closed the heading-tool, as it forms the end A into a head,also further upsets the taper portion B of the blank, until it tills thedie and finishes the square partof the bolt. l

Ordinarily blanks for bolts that are squared in heading are formed withthe end D, (see Fig. 2,) with parallel sides, and of a size sut'- icientto be formed into a square equal to the diameter of the end E, which endE is to remain round when finished, the same as the end C in Fig. 1.

These blanks are squared by pressure between like dies, and in likemanner herein described for squaring the base of the taper B; but as thewhole of the square in the ordinary style is squared all at one time, itwill be plainly seen that a great amount of pressure must be used toclose the dies, while sometimes the same may not be closed as much as atother times, thus making the-size of the squares vary and the cornersrounded or blunt.

By my invention I produce a blank from which bolts can be formed thesquare portion of which will be of a uniform size and with angularcorners, thus producing a better article without increasing the cost orchanging the squaring and heading tools. The wear ot' thesquaring-diesin forging bolts from blanks of my invention is much lessthan itis in forging bolt-s from ordinary blanks.

What I claim as new, and desireA to secure by Letters Patent, is-

A round bolt-blank, consisting of the round ends A and C and the roundtaper B, substantially as shown and described, and for the purposes setforth.

JAMES B. CLARK.

